The indoor communication technologies are promising deployment strategies to get better energy efficiency.
This is because of the favorable channel conditions they can offer between the transmitters and receivers.
Moreover, by separating indoor traffic from outdoor traffic, the marcocell BS will have less pressure in allocating radio resources and can transmit with low power, resulting in a significant reduction in energy consumption.
VLC and mm-wave technologies can also be considered as energy efficient wireless communication solutions to be deployed in 5G wireless systems.
For example, in VLC systems the consumed energy in one bulb is much less than that in its RF-based equivalents for transmitting the same high-density data.